Dr. de Waal, who is director of the Living Links Center at Emory University, argues that all social animals have had to constrain or alter their behavior in various ways for group living to be worthwhile. These constraints, evident in monkeys and even more so in chimpanzees, are part of human inheritance, too, and in his view form the set of behaviors from which human morality has been shaped.

Many philosophers find it hard to think of animals as moral beings, and indeed Dr. de Waal does not contend that even chimpanzees possess morality. But he argues that human morality would be impossible without certain emotional building blocks that are clearly at work in chimp and monkey societies.

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These four kinds of behavior — empathy, the ability to learn and follow social rules, reciprocity and peacemaking — are the basis of sociality.

Dr. de Waal sees human morality as having grown out of primate sociality, but with two extra levels of sophistication. People enforce their society’s moral codes much more rigorously with rewards, punishments and reputation building. They also apply a degree of judgment and reason, for which there are no parallels in animals.

Biologists are allowed an even smaller piece of the action by Jesse Prinz, a philosopher at the University of North Carolina. He believes morality developed after human evolution was finished and that moral sentiments are shaped by culture, not genetics. “It would be a fallacy to assume a single true morality could be identified by what we do instinctively, rather than by what we ought to do,” he said. “One of the principles that might guide a single true morality might be recognition of equal dignity for all human beings, and that seems to be unprecedented in the animal world.”

Dr. de Waal does not accept the philosophers’ view that biologists cannot step from “is” to “ought.” “I’m not sure how realistic the distinction is,” he said. “Animals do have ‘oughts.’ If a juvenile is in a fight, the mother must get up and defend her. Or in food sharing, animals do put pressure on each other, which is the first kind of ‘ought’ situation.”

Dr. de Waal’s definition of morality is more down to earth than Dr. Prinz’s. Morality, he writes, is “a sense of right and wrong that is born out of groupwide systems of conflict management based on shared values.” The building blocks of morality are not nice or good behaviors but rather mental and social capacities for constructing societies “in which shared values constrain individual behavior through a system of approval and disapproval.” By this definition chimpanzees in his view do possess some of the behavioral capacities built in our moral systems.